https://www.linux.com/wp-content/uploads/2025/12/k... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
10images28 KB
0oversized-0 KB
8legacy format
1missing dimensionsCLS risk
Set explicit width and height to prevent CLS.
Why this matters
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
B
HTTP/3 (QUIC)
HTTP/3 not advertised
REVIEW
HTTP/3 not advertised
Info::
i
HTTP/3 (QUIC) is not advertised
HTTP/3 isn't advertised via Alt-Svc and the worker didn't negotiate h3. HTTP/3 reduces handshake latency (1-RTT instead of 2-3 RTTs) and is more resilient on lossy connections. Most modern CDNs (Cloudflare, Fastly, AWS CloudFront, Google Cloud CDN) support HTTP/3 with a single config switch -- consider enabling for mobile-heavy workloads.
C
Compression Algorithm
Action
Main response served uncompressed
REVIEW
Main response served uncompressed
Info::
i
Main HTML response has no Content-Encoding (uncompressed)
The main HTML document is served without compression. The Text Compression section above lists the broader picture; for the main response specifically, even gzip would shave ~70-80% off most text payloads.
C
Main HTML Cache-Control
Action
Main HTML max-age=86400 (~1440min) is aggressive
REVIEW
Main HTML max-age=86400 (~1440min) is aggressive
Warning::
!
Main HTML cached for 1440 minutes -- risks stale auth / SPA state
Long max-age on the main HTML document means users may see outdated auth state, SPA shells, or A/B variants until the cache expires. Consider Cache-Control: no-cache (or max-age=300) for HTML and let your hashed assets (JS/CSS/images) carry the long cache instead.
Got: public, max-age=86400
B
Server-Timing Observability
No Server-Timing header found
REVIEW
No Server-Timing header found
Info::
i
No Server-Timing header found
Server-Timing exposes backend timing breakdowns to browser DevTools (e.g., `db: 45ms; render: 120ms; cache: 2ms`). Useful for diagnosing slow pages without backend log access. Most modern frameworks (Next.js, Cloudflare Workers, Fastly) emit it automatically; absence on a managed platform usually means telemetry headers are stripped at the edge.
B
JavaScript Blocking
2 JS blocking issue(s) detected
REVIEW
2 JS blocking issue(s) detected
Warning::
!
23 render-blocking <script src> tag(s) without async/defer
Each `<script src=...>` without `async`, `defer`, or `type="module"` blocks HTML parsing while the browser fetches and executes it. The block lasts the entire round-trip + execution time -- on slow networks this translates directly into LCP delay. Add `defer` (executes after parse, in source order) for scripts that interact with the DOM, or `async` (executes whenever ready) for analytics / independent scripts. Module scripts (`type="module"`) are deferred by default.
Warning::
!
Total JS execution time is 4.7 s -- over the 3.5s budget
Total JavaScript execution (parse + compile + run) across all scripts exceeds 3.5 seconds. On low-end devices that becomes 7-15+ seconds and shows up directly in TBT and INP. Reduce by: tree-shaking unused dependencies, code-splitting (dynamic `import()`), removing or deferring third-party tracking, and replacing heavy frameworks where they're not needed.
C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW
Green Hosting
No green hosting detected
A+
Text Compression
All text resources are compressed
PASS
All text resources are compressed
Info::
✓
All text resources are compressed
All text resources are properly compressed.
A+
Font Loading
4 fonts (147 KB)
PASS
4 fonts (147 KB)
Info::
i
4 font(s) use font-display: swap (FOUT risk but functional)
Web fonts
4
147 KB total
Render-blocking
0
of 4
Dominant font-display
swap
Most common across fonts
Font loading timeline
TransferFOIT (block)FOUT (swap)
newspaper.woffwoffswap
Size34 KB
Load time18 ms
Start48 ms
RiskFOUT — text flashes from fallback to web font
Convert to woff2 for ~30% smaller file size
newspaper.woffwoffswap
Size34 KB
Load time15 ms
Start291 ms
RiskFOUT — text flashes from fallback to web font
Convert to woff2 for ~30% smaller file size
KFO7CnqEu92Fr1ME7kSn66a...woff2swap
Size37 KB
Load time66 ms
Start295 ms
RiskFOUT — text flashes from fallback to web font
memvYaGs126MiZpBA-UvWbX...woff2swap
Size42 KB
Load time70 ms
Start296 ms
RiskFOUT — text flashes from fallback to web font
Optimization checklist
Preload critical fonts (priority=high)
Use woff2 format for all fonts
Set font-display to swap, optional, or fallback
Subset large fonts (≤100 KB each)
Fixing the unchecked items could save ~21 KB and ~42 ms
A+
Resource Caching
All resources properly cached
PASS
All resources properly cached
Info::
✓
No caching issues found
All static resources have appropriate caching headers.
A+
Critical Rendering Path
No render-blocking resources
PASS
No render-blocking resources
Info::
✓
No render-blocking resources detected
A+
Resource Hints
2 hints, 0 missing preconnects
PASS
2 hints, 0 missing preconnects
Info::
✓
Page uses 2 resource hint(s)
Current Resource Hints
preconnect—
preload
1
dns-prefetch
1
prefetch—
2 resource hints configured
A+
LCP Image Preload
LCP preload audit not available
PASS
LCP preload audit not available
Info::
✓
LCP image preload audit not available for this scan
A+
Server Response Intelligence
2 server-response signal(s) detected
PASS
2 server-response signal(s) detected
Info::
✓
`Vary` header declared: Cookie, Cookie
The page declares a `Vary` header, telling downstream caches which request headers the response varies on. Critical for content-negotiated responses (compression, language, cookies, device class).
Info::
i
No `ETag` or `Last-Modified` -- conditional GET not supported
Without either header, browsers can't issue conditional GETs and refresh always re-downloads the full response body even when nothing changed. Add `ETag: "<hash>"` (or `Last-Modified: <date>`) on cacheable responses; the server returns 304 Not Modified when the client's cached copy is still valid, saving bandwidth.
Each `<link rel="stylesheet">` without a non-blocking `media` attribute holds up the first paint. Browsers download all of them before painting any content. Consolidate into 1-2 critical-path stylesheets; defer non-critical CSS via `<link rel="stylesheet" media="print" onload="this.media='all'">` or via the loadCSS pattern; inline above-the-fold CSS in `<style>` to short-circuit the request entirely.
A
HTTP Caching
max-age=86400 (1 day)
PASS
max-age=86400 (1 day)
Info::
✓
Cache-Control header is set
Got: public, max-age=86400
Info::
✓
Effective TTL: 1 day (max-age=86400)
Info::
i
No ETag or Last-Modified header
Conditional requests (304 Not Modified) are not possible without validators.
Cache-Control
public, max-age=86400
Directive
Value
Meaning
public
—
Any cache may store this response
max-age
86400
Cache for 1 day
Effective TTL: 86400 seconds
Network Waterfall
159 requests over 4801ms
INFO
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
86%of JavaScript execution is third-party
First-party Third-party4057ms · 1449KB · $76/mo
Script
Category
Execution
Transfer
Unused
Monthly Cost
Verdict
HubSpot Analytics
js.hs-analytics.net
Analytics
600ms
45 KB
—
$11/mo
Costly
Drift
js.driftt.com
Chat
593ms
63 KB
55%
$11/mo
Costly
www.linux.com
www.linux.com
Other
419ms
37 KB
—
$8/mo
Costly
Facebook Pixel
connect.facebook.net
Advertising
288ms
67 KB
31%
$5/mo
Costly
Google Tag Manager
www.googletagmanager.com
Tag Manager
273ms
160 KB
39%
$5/mo
Costly
pagead2.googlesyndication.com
pagead2.googlesyndication.com
Other
253ms
162 KB
74%
$5/mo
Costly
Facebook Pixel
connect.facebook.net
Advertising
252ms
105 KB
33%
$5/mo
Costly
Google Tag Manager
www.googletagmanager.com
Tag Manager
249ms
170 KB
42%
$5/mo
Costly
Google Tag Manager
www.googletagmanager.com
Tag Manager
209ms
138 KB
45%
$4/mo
Costly
www.linux.com
www.linux.com
Other
138ms
35 KB
—
$3/mo
Optional
js-agent.newrelic.com
js-agent.newrelic.com
Other
134ms
20 KB
—
$3/mo
Optional
lfx-segment.platform.linuxfoundation.org
lfx-segment.platform.linuxfoundation.org
Other
100ms
84 KB
33%
$2/mo
Optional
www.linux.com
www.linux.com
Other
94ms
47 KB
77%
$2/mo
Optional
LinkedIn Insight
snap.licdn.com
Advertising
80ms
18 KB
—
$2/mo
Optional
js.hsadspixel.net
js.hsadspixel.net
Other
79ms
5 KB
—
$1/mo
Optional
js.usemessages.com
js.usemessages.com
Other
68ms
28 KB
—
$1/mo
Optional
Google Tag Manager
www.googletagmanager.com
Tag Manager
65ms
160 KB
69%
$1/mo
Optional
pagead2.googlesyndication.com
pagead2.googlesyndication.com
Other
56ms
56 KB
55%
$1/mo
Optional
js.hubspot.com
js.hubspot.com
Other
54ms
28 KB
—
$1/mo
Optional
Google Analytics
www.google-analytics.com
Analytics
51ms
21 KB
—
$1/mo
Optional
HubSpot Analytics
Analytics
Costly
Execution600ms
Transfer45 KB
Monthly Cost$11/mo
Drift
Chat
Costly
Execution593ms
Transfer63 KB
Unused55%
Monthly Cost$11/mo
www.linux.com
Other
Costly
Execution419ms
Transfer37 KB
Monthly Cost$8/mo
Facebook Pixel
Advertising
Costly
Execution288ms
Transfer67 KB
Unused31%
Monthly Cost$5/mo
Google Tag Manager
Tag Manager
Costly
Execution273ms
Transfer160 KB
Unused39%
Monthly Cost$5/mo
pagead2.googlesyndication.com
Other
Costly
Execution253ms
Transfer162 KB
Unused74%
Monthly Cost$5/mo
Facebook Pixel
Advertising
Costly
Execution252ms
Transfer105 KB
Unused33%
Monthly Cost$5/mo
Google Tag Manager
Tag Manager
Costly
Execution249ms
Transfer170 KB
Unused42%
Monthly Cost$5/mo
Google Tag Manager
Tag Manager
Costly
Execution209ms
Transfer138 KB
Unused45%
Monthly Cost$4/mo
www.linux.com
Other
Optional
Execution138ms
Transfer35 KB
Monthly Cost$3/mo
js-agent.newrelic.com
Other
Optional
Execution134ms
Transfer20 KB
Monthly Cost$3/mo
lfx-segment.platform.linuxfoundation.org
Other
Optional
Execution100ms
Transfer84 KB
Unused33%
Monthly Cost$2/mo
www.linux.com
Other
Optional
Execution94ms
Transfer47 KB
Unused77%
Monthly Cost$2/mo
LinkedIn Insight
Advertising
Optional
Execution80ms
Transfer18 KB
Monthly Cost$2/mo
js.hsadspixel.net
Other
Optional
Execution79ms
Transfer5 KB
Monthly Cost$1/mo
js.usemessages.com
Other
Optional
Execution68ms
Transfer28 KB
Monthly Cost$1/mo
Google Tag Manager
Tag Manager
Optional
Execution65ms
Transfer160 KB
Unused69%
Monthly Cost$1/mo
pagead2.googlesyndication.com
Other
Optional
Execution56ms
Transfer56 KB
Unused55%
Monthly Cost$1/mo
js.hubspot.com
Other
Optional
Execution54ms
Transfer28 KB
Monthly Cost$1/mo
Google Analytics
Analytics
Optional
Execution51ms
Transfer21 KB
Monthly Cost$1/mo
These scripts may cost more than they're worth
HubSpot Analytics adds 600ms and costs ~$11/month
Drift adds 593ms and costs ~$11/month
www.linux.com adds 419ms and costs ~$8/month
Facebook Pixel adds 288ms and costs ~$5/month
Google Tag Manager adds 273ms and costs ~$5/month
pagead2.googlesyndication.com adds 253ms and costs ~$5/month
Facebook Pixel adds 252ms and costs ~$5/month
Google Tag Manager adds 249ms and costs ~$5/month
Google Tag Manager adds 209ms and costs ~$4/month
86% of JavaScript execution time is spent on third-party scripts. Consider auditing which scripts are essential.
Why this matters
When third-party JS execution time exceeds your own, performance gains from frontend work are capped by code you don't own.
Learn more ▾▴
Every millisecond of third-party JS competes with your own for main-thread time. If their share is bigger than yours, optimization on your code base barely moves the needle. Audit, defer, or remove third-parties before further frontend optimization. Use Lighthouse's third-party audit to identify the worst offenders.
Source: web.dev
HubSpot Analytics takes 600ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
Why this matters
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
Drift takes 593ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
Why this matters
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
55% of Drift's code is unused. The script may be loading features you don't use.
Why this matters
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
www.linux.com takes 419ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
Why this matters
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
Facebook Pixel takes 288ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
Why this matters
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
Google Tag Manager takes 273ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
Why this matters
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
pagead2.googlesyndication.com takes 253ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
Why this matters
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
74% of pagead2.googlesyndication.com's code is unused. The script may be loading features you don't use.
Why this matters
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
Facebook Pixel takes 252ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
Why this matters
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
Google Tag Manager takes 249ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
Why this matters
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
Google Tag Manager takes 209ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
Why this matters
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
77% of www.linux.com's code is unused. The script may be loading features you don't use.
Why this matters
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
69% of Google Tag Manager's code is unused. The script may be loading features you don't use.
Why this matters
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
55% of pagead2.googlesyndication.com's code is unused. The script may be loading features you don't use.
Why this matters
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.